Electric switch



March 11, 1952 H. B. SPEAKER ELECTRIC SWITCH Filed Oct. 12, 1949 FIG.|

FIG. 2

FIG.4

IN V EN TOR.

HARRY B. SPEAKER ATTORNEY Patented Mar. 11, 1952 UNITED STATE S PATENT OFF ICE ELECTRIC SWITCH Harry B. Speaker, Neptune, N. J assignor to theUnited States of America as represented by the :Secretary of the ArmyApplication October 12, 1949, Serial No. 121,045

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 6 Claims.

closed by subjecting the switch to acceleration- 101 .3 P riod of time.Although said switch is :Darticu'arly "useful in an ordnance projectile,or the like, '10). the purpose of closing an electric:circuitiordetonating its war head, its usefulness is not limitedthereto.

{Bhepresent invention is made up of two chambers which intercommunicatethrough a conduit pierced :by a restricted delay channel. Saidchambersand channel contain a mobile electrical conductor (such asmercury). Each chamber also contains a gas (such as .air) which is more'rarifiedin one chamber ("lower pressure chamber) than in the other(higher pressure chamber). .-As a result of this pressure differential,whfin the switch ,is unoperated (at rest), said mobile conductor ismaintained in a condition of balance, at diiierent levels or heights inthe two chambers. For convenience I will refer to these levels in thetwo chambers as unoperated levels.

When the device is subjected to acceleration, said mobile conductorflows from the lower pressure chamber to the h gher pressure chamber,until a new condition of balance is effected, with said .mobileconductor atother levels in the two chambers (which I will refer to asoperated levels). This flow reouires a certain length of time. which isa function of the viscosity of the mobile conductor, the pressuredifferential. the relative heights .of the mobile conductor in the twochambers, the cross-sectional size of the delay channel and the degreeof acceleration applied.

:One or more electrical terminals are suitably posit oned in one or bothchambers so as to be in electrical contact with the mobile conductor,either in its unoperated condition (at rest) or in its operatedcondition (after the application of acceleration for a requisite periodof time). If, in the unoperated condition, said mobile conductor is incontact with a terminal, then a circuit incorporating said .terminal maybe opened upon the application of a predetermined amount ofacceleration. If, however, in the unoperated condition, the mobileconductor is not in contact with a terminal. then the closing ofacircuit may ,be accomplished by acceleration.

An object of the present invention is to provide an electrical switchoperated by acceleration and, moreparticularly, to provide such a switchhaving a time delay.

Another object is .to provide such an acceleration actuated switch,wherein a circuit may be either opened or closed.

Still another object is to provide such a switch which returns to its atrest, or unoperated, condition after acceleration has ceased and,particularly, which returns .to its said unoperated condiv tion withouthaving efiected any circuit change, in the event that an insufficientamount of acceleration-has been applied.

Yet another object is to provide such a switch which may be relativelysmall in size, simple, inexpensive and completely enclosed, and whichneed have no moving structural parts.

In the drawings, which are .drawn to an enlarged scale:

Figure 1 is .a vertical cross section of one embodiment of the presentinvention in an at rest or unoperated condition,

Figure 2 shows the embodiment of Figure 1 in its operated condition(after having been subjected to a requisite amount of acceleration),

Figure 3 is a vertical cross section of a second embodiment of thepresent invention in its at rest or unoperated condition; and

Figure 4 similarly shows said second embodiment when sufiicientacceleration has been applied to operate it.

Referring now to Figures 1 and 2, the first embodiment of the presentinvention there illustrated comprises cy-indrical lower pressure andhigher pressure chambers II, I3 which intercommunicate by Way of aconduit or tube I5 pierced by a relatively restricted delay channel I6.The walls of said chambers II, I3 and tube I5 may be of any suitabledielectric material (such as glass or plastic) which has suflicientstructural strength to take the strains of operation of the device.

The chambers II, I3 are partially filled with mercury IT, or some othersuitable mobile electrical conductor which may flow through the delaychannel I6. When in its unoperated condition (i. e. when it is at rest),there is a higher head or level of mercury I1 in the lower pressurechamber I I than in the higher pressure chamber I3, because a suitablegas l8 (as air) in the space above the mercury in the chamber II hasbeen rarified to a greater degree than a gas 20 in the chamber I3.

' The lower pressure chamber I I is provided with i two electricalterminals I9 which extend through pressure chamber I3.

the walls of said chamber and are suitably hermetically bonded to saidwalls. The higher pressure chamber I3 is likewise provided with a pairof electrical terminals 2|. It will be noted that the terminals I9 arelocated below the unoperated level of the mercury I! in chamber II (asshown in Figure 1), but above the operated level of the mercury in saidchamber II (as shown in Figure 2). Similarly the terminas 2| in thehigher pressure chamber I3 are located intermediate the unoperated andoperated levels (shown respectively in Figures 1 and 2) of the mercuryI! in said chamber I3.

Re erring now to Figures 3 and 4 of the draw-' ing, the second form ofmy invention there illus- Fach of the chambers 25, 21 is partiallyfilled with mercur 33, or some other suitable mobile conductor whi h mayflow through the delay channel 32. The lower end of t e tube 3I' extendsdown far enough sothat it is always submer ed in the mercury 33 at anyoperating level I of the mercury in the hi her pressure chamber 21. Thegas 3 above the mercury 33 in the lower pressu e chamber 25 has a lowerpressure than t e gas 3'! in the hi her pressure chamber 21, With t e reult that, when unoperated, there is a relativel hi h level of mercury 33in said chamber 25 and a relatively low level of mercury in said chamber21.

Extending through the side walls of the lower pres ure chamber 25 andhermetically sea ed the ein are a pair of electrical te minals 39. Thehi her pressure chamber 27 is similarly provided with a pair ofelectrical terminals 4|. Said terminals 39 are positioned intermediatethe unoperated and operated levels (shown respectively in Figures 3 andi) of mercury 33 in the chamber 25, and. similarly, the terminals 4! arelocated at a position which is intermediate the unoperate and operatedlevels of mercury in the chamber 21.

Although not shown in the drawing because not necessarily a part of thepresent invention, a device embodying the present invention would, insome applications, be mounted in gimbals so as to maintain the devicelevel at all times.

In the operation of the form of my device illustrated in Figures 1 and2, the elements are as shown in Figure 1 when the device is at rest(unoperated). Due to the differential pressure of the gases I8, 20 inthe chambers II, I3, the mercury I I achieves a state of balance at theunoperated levels shown in Figure 1. As there shown, the level of themercury I! is higher in the lower pressure chamber I I than in thehigher The terminals I9 and/or 2! may be connected into any suitablecircuit or circuits (not shown). As, when unoperated, the terminals I9are submerged in the mercury I I, any circuit connected thereto isclosed at said terminals. However, as the terminals 2| are then abovethe unoperated level of the mercury I'E in the higher pressure chamberI3, any circuit connected through said terminals is open.

During operation, the device is subjected to an acceleration. When thisoccurs, mercury I] ZfiQWS small size of the delay channel I6 as comparedn v.) v)

to the viscosity of the mercury I'I, this flow will continue for afinite period of time until a new state of balance is reached (Figure2). It will be seen, that the terminals I9 are now above the operatedlevel of the mercury H in the lower pressure chamber I I so that anycircuit in which they are connected will have been opened. Also, theterminals ZI are now submerged in the mercury I I in the higher pressurechamber I3 so that any circuit in which they are connected will havebeen closed. As soon as the acceleration ceases, the differentialpressure or" the gases I8, 20 will cause the mercury I! to flow back tothe unoperated levels (Figure 1).

It will be understood that a certain combination of acceleration andtime are necessary before the mercury I'I reaches the operated levels(Figure 2) so as to efiect electrical disconnection of the terminals isand connection of the terminals 2I. advance, and the sizes of thechambers I I, I3, the cross sectional area of the delay channel I6, theamount of mercury Il, the relative pressures of the gases i8, 28, therelative positions of the terminals 9, 2i and other factors may bechosen to meet any desi ed operating characteristics. The basicprinciple of operation, however, will remain the same.

Although two sets of terminals I9, 2I have been shown. it will beunderstood thatthis is merely illustrative and 'a particular embodimentmay have only one of the sets or, if two sets are 'pro-' vided, only onemay be" used. Also one terminal of each set i9, 2! may be at a lowerlevel so as to" be submerged in the mercury ll during all stages ofoperation. Again, a plurality of terminals may be used so as to achieveany desired sequential operation. Thus, for instance, several sets ofterminals (not shown) may be disposed at different levels so as to openor close circuits at differenttime intervals.

The operation of the second embodiment (Figures 3 and 4) is similar tothe operation already described, the lower pressure and hi her pressurechambers 25, Z'I being similar to the chambers II and I3, respectively,of Figures 1 and 2. This second embodiment may be considered moresatisfactory for some installations, because of its compactness andunitary form, and it also has the advantage of having the conduit 3!disposed entirely within the cylindrical structure so as to be lesssubject to damage.

The present invention may be used irrespective of the direction in whichthe acceleration is applied. Thus, in a projectile which should reach acertain altitude before its war head is triggered, the acceleration actsin a vertical direction. But in a centrifugal machine, the accelerationmay be applied horizontally or, as a matter of fact, in any direction.The heights of the mobile conductor are then efiective along the axis ofacceleration. Thus, in the present patent application, such terms asunoperated level, operated" level, etc., are to be considered relativeto a particular axis of acceleration, which may or may not be verticallyoriented.

While there have been described what are at present considered to bepreferred embodiments of my invention, it will be obvious to thoseskilled in the art that changes and modifications may be made thereinwithout departing from the invention and it is aimed in the appendedclaims to Obviously this may be calculated in cover all such changes andmodifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. An acceleration operated electric switch comprising, a closed lowerpressure chamber, a closed higher pressure chamber, a conduit providedwith a delay channel interconnecting said chambers, a mobile electricalconductor within said chambers and channel, gas in each of saidchambers, the gas in said lower pressure chamber being more rarifiedthan the gas in said higher pressure chamber, said mobile conductorextending, in one of said chambers, to unoperated and operated levelswhen said switch is in unoperated and operated conditions respectively,at least one electrical terminal in said last-mentioned chamber at aposition intermediate said unoperated and operated levels, so that, whensaid mobile conductor is at one of said levels, it is in electricalcontact with said terminal and, when it is at the other of said levels,it is electrically disconnected from said terminal.

2. A switch as defined in claim 1, wherein said chambers are juxtaposedlaterally relative to the axis of acceleration.

3. A switch as defined in claim 1, wherein said chambers are arranged intandem along the axis of acceleration.

4. An acceleration operated electric switch comprising two closedchambers, a conduit provided with a delay channel interconnecting saidchambers, a mobile conductor in said channel and chambers, a gas in eachchamber, said gas in one chamber being more rarified than said gas inthe other, said conductor extending to unoperated and operated levels ineach of said chambers, an electrical terminal in one of said chamberspositioned intermediate the unoperated and operated levels in saidchamber.

5. An acceleration operated electric switch comprising, a closed lowerpressure chamber, a closed higher pressure chamber, a conduit providedwith a delay channel interconnecting said chambers, a mobile electricalconductor within said chambers and channel, gas in each of saidchambers,

the gas in said lower pressure chamber being more rarified than the gasin said higher pressure chamber, said mobile conductor extending, insaid lower pressure chamber, to an unoperated level when said switch isin an unoperated condition and to an operated level, which is lower,when said switch is in an operated condition, at least one electricalterminal in said lower pressure chamber at a position intermediate saidunoperated and operated levels, so that, when said mobile conductor isat said unoperated level, it is in electrical contact with said terminaland, when said mobile conductor is at said operated level, it iselectrically disconnected from said terminal.

6. An acceleration operated electric switch comprising, a closed lowerpressure chamber, a closed higher pressure chamber, a conduit providedwith a delay channel interconnecting said chambers, a mobile electricalconductor within said chambers and channel, gas in each of saidchambers, the gas in said lower pressure chamber being more rarifiedthan the gas in said higher pressure chamber, said mobile conductorextending, in said higher pressure chamber, to an unoperated level whensaid switch is in an unoperated condition and to an operated level,which is higher, when said switch is in an operated condition, at leastone electrical terminal in said higher pressure chamber at a positionintermediate said unoperated and operated levels, so that, when saidmobile conductor is at said unoperated level, it is electricallydisconnected from said terminal and, when said mobile conductor is atits operated level, it is in electrical contact with said terminal.

HARRY B. SPEAKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,600,121 Mazade Sept. 14. 19261,695,546 Goodhue Dec. 18, 1928 2,236,790 Erich Apr. 1, 1941 2,404,179King July 16, 1946

